Originally posted by Game4Fun:

They will not dissapear after some time? There is not way to deal with them if you are not strong enought to fight them? Sounds not good if you have a base where u spent a lot of time to build it and it got destroyed and trolls made there a new home.

The way the raids work is that you are (almost) always strong enough to fight them. They escalate based on your progress in the game. Even the dreaded Trolls are child's play once you figure the game out a little bit. The enemies try to attack YOU, not your base. Don't hide behind your base and they won't smash it. As soon as you see a raid coming, get away from your buildings and kill it. Or, if you really can't handle it, run around for a few minutes and the raid will end. You might also find that you can get some help defending your base, not gonna spoil anything though.